LMT01 temperature sensor~

This feature is included only in tasmota-sensors and tasmota32 binaries

When compiling your build add the following to user_config_override.h:

#ifndef USE_LMT01 
#define USE_LMT01      // Add support for TI LMT01 temperature sensor, count pulses on single GPIO (+0k5 code)
#endif

The Texas Instruments LMT01 is 2-pin digital output temperature sensor that converts temperature directly to a sequence of digital pulses, reading a range from -50°C to +150°C with up to 0.5°C accuracy. It is available in a DIY-friendly small TO-92 package.

Connection is by a single GPIO to count the pulses, which needs a driver transistor to convert the small current changes into logic level voltage swings.

LMT01 data sheet
LMT01 product page with links to evaluation board and training video and sample code.

Limitations of current implementation:

Only the simple linear conversion is used. The datasheet suggests the use of a look-up table to improve the accuracy at the edges of the range, this is not yet implemented.
The sensor code only supports one LMT01 instance.

Configuration~

Choose a pin GPIOx. The GPIO can be connected to the LMT01 via a NPN transistor, so current pulses pull the GPIO line low: see Figure 32 in the LMT01 datasheet.

In the Configuration -> Configure Module page assign:

GPIOx to LMT01 Pulse

After a reboot the sensor will be detected and displayed. If the connection is not working, the pulse counting will timeout and you will see null displayed for the temperature.